Control of aircraft



Sept. 3, 1946.

' E. A.4 STALKER CONTROL OF AIRCRAFT Filed Aug. 22, 1940 2 ASheets--Sheei'i 1 Wwummmwwmmwmw E. A. v'sTALKl-:RA 4 l CONTROL oF AIRCRAFT Filed Aug. 22 ,1 1940.

" INVENTOR 21 sheets-sheet 2 Patented Sept. 3, 1946 .d "UNITED STATES PATENT OFFICEY CONTROL oF AIRCRAFT Edward A. Stalker, Ann Arbor, Mich. Application August 22, 1940, Serial No. 353,712

` 1o claims." (o1. 24A-f90) My'invention` relates to aircraft and particularlyto the aerodynamic control. It has for its objects, rst'to provide la means capable of producing powerful rolling moments, second to provide a means of producing a powerful y-awing moment, Ithird to provide a lateral control means in which the adverse yawing moment is reduced or converted to .a favorable moment, fourth .to provide a simple and effective means of lcontrolling a flow through a slot, ith to provide a properly proportioned aileron for Iaction with a slot flow, sixth to provide a wing with a jet discharge for boundary layer control. Other objects will appear from the appended specification and drawings.

V:I accomplish the above objects by the means illustrated in the accompanying :drawings in whichvFigure 1 is a plan View of the aircraft;

Figure 2 is a fragmentary plan view of Ia wing;

Figure 3 is a section along .the line 3-.3 in Figure 2;

Figure 4 isa section along line 4*-4 in Figurel 2; and 1 Figure 5 is Ia section along line 5 5 in Figure 2. Figure 6 is a fragmentary plan view of a tail plane;

Figure 7 is a, fragmentary elevation of the planes in Figure 6; y

Figure 8 is a section along the line 8 8 in Figure 6 l n n 1 A Figure 9 is Ithe same section as Figure 8 with the naps displaced;

Figure 10 isa section through the surface flap to show the T-lug; and

Figure 11 is a spanwise section through lthe upper surfaces of flaps 20 and 2| lto show the T-lug in the T-slot.

In banking an airplane for a turn the ordinary aileron produces a large yawing moment in opposition to the turn. This is undesirable since the rudder must be used to produce a, large counter moment. It is desirable that the yawing moment from the ailerons be quite near zero or slightly favorable to the turn.

This invention describes a means of producing very powerful rolling moments by boundary layer control using small amounts of energy and .accompanied by a yawing moment of any .desired magnirtude, even of zero value if desired.

The great rolling moment is obtained with an aileron having a unique upper curvature so that when it is depressed the upper surface of the wing as a whole has a smooth curvature of gencrous radius.- Y Boundary layer control can then be effected on such a wing with very low energy expended in the jet which is blown outward along the surface.

The jetV energizes the boundary layer and provides a .thrust from the mass reaction which ounteracts the adverse yawing moment from the aileron. y Referring particularly to .the drawings, the wing is I, the fuselage is 2 and the tail group is 3.

The wing has ,the aileron 4 near the tip. It has a normal upper surface contour so as to produce a reversal of curvature in ythe chordwise section of .the wing, but when the aileron is depressed the wing upper contour is changed to a curvature free of reversals and of large radius. Seegdottedportionpof aileron in Figure 5; With such -a curvature the energy required for energiaingtheboundary layer is small. If the radius of curvature Aissinall the power necessary to compel the ilowgto` follow .the flap is hugetoo large for practical purposes. d

Hence one of ,the main features of this invention embraces the discovery that a large radius is necessary at the ap juncture with the main portion of the wing.

.The contour of the wing also can be described in terms of the depression of the concavity below a chordwise tangent .to-the opposite sides of the concavity or in terms of the radius of curvature of the 4extradoses. The average radius of curvature of a iap extrados should be less than that of the rear portion of the fore or main wing body so as to produce the concavity and so as to produce a smooth curvature when the flap is depressed. By average radius of curvature is meant the average radius of a group of small segments of the extrados.

The aileron is carried on the flap 5 which has the induction slot 8 leading into the wing interior in `communication with the blower 9. It discharges its air through the slots l0 and l I. The former is in the flap 5 and the latter is formed between the flap and the upper'wall of the aileron to facilitate rotation of the aileron and to control the slot flow with the minimum of mechanism.

The blower is driven from the engine by means of the propeller in the manner described in my U. S. Patent No'. 1,913,644.

It is important that Ithe lateral control moments available be at their maximum when the airplane is landing without power. For this reason I have provided' a windmill to drive the blower 9. In this case the windmill is the propeller 9a on the engine 96. The windmill is free to drive the blower relieved of the engine torque be- 3 cause of an automatic clutch between the propeller and the engine.

The blower communicates with the slots I and I I through the passage I2.

Since the aileron 4 is carried .on the flap 5 it is moved with and is rotatable up and down relative rto 5 for any position of 5. Flap 6 is also carried by flap 5 and is rotated coincidentally with 5 by a suitable mechanism not shown. Y

The aileronis moved by means 'ofthe meclia'-- nism shown in Figure 5. The sprocket I3 is actuated from the fuselage by a. chain I3a. `It turns the shaft I4 supported in the bearings I5 fixed to flap 5 and moving with it about the-.hinge I8. This shaft is connected to shaft I6 by the universal joint I'I. The shaft I6`is"threadedin"-v ternally and accommodates the "externally threaded shaft Ilia articulated to the aileron at Ib. A rotation of I6 moves Ia axially'and so rotates the aileronrelative to the ap 5. Ailerons on opposite sides of the iplan'eof syin'metry Aof the airplane are 'operated differentially in the 'conventional manner. That is, one goe's up while the other -goes down. The -pilots'stick is 13b and rotates the torque tube fand sprocket I3c which carries the chain i3d connected to clia'ir'i At the time of landing the flaps 5 and 6 are depressed to give a high arching 'of the 'wing section, as vshown dotted'in Figurei. 'Ih'e blower 9 is driven by the propeller `racting .as `l`a windmill if the engine is not running.

'Air is inducted through the slots '8 and v'3a land discharged through .the s'lo'ts I0 'andfI'L It will be clear that when the'aileron is fully 'depressed r the slot i'l is wide open `While Wliei'rit 'is 'fully raised the slot II is closed. Hence when' the aileron is y'producing `*anupfore, the jet visprinduoing a forward thrust which Vwill vi:o uriter-act the added drag arising from the 4lift"enge'ridered by the aileron. It is well known 'that anfinrease in lift is -accompanied by an increase Iin induced drag.

When the aileron is 'up A'ard'rtlfie jet elim-i'- nated there is produced a down-'force onfth'e wing without ya forward thrust zfrom the fjet.- Thus there is a turning or yawing :momen-t 'the' jet on the vside of 4the down aileron `andjhence the yawing moment islfa'vorable .to tlie'tur'i faccompanying the banking :of the "airplane, yThis is the desiredl situation.

'It will -now Vbe understoodthat ihave `fdiszlesed a control :surface of l*such'fbrn :s to Lrrfalle prac'- tical the use of boundary `le'fy'er control in lproducing'a powerful-rollingfmbrneirt. The scalloped wing section is essential tothisso las'itoprovide a large radius of curvature upon v"v'vhicli to -`con` trol the boundary layer. This radius :of curvature has a critical value below ``4wlf'iiohf'ithe `jipower required 'for boundary layer control*"becomes exorbitant. The *radiusV of 'curvature should gbe greater than tnejthiekness ef the wingnearfthe juncture of the flap and'mainiportion of'tliewing.

Furthermore, Ihaveshownhowto control jets at the wing tips'sirnplyso'to'producea favorable yawing moment to accompany the roll from the ailerons. To do this effectively'the discharge slots should be in the vrear one-half of the wing and preferably in the iiaps themselves. Any induction slots should lie `ahead vof the `discharge slots since if the vjet is sucked into the wing it does not furnish a thrust.

In order to exert athrust tofproduce'a favorable yawing moment the jet must be producedby kfa `open up the `slot on the convex side.

power and so a power driven blower is employed in the aircraft.

Figures 6 to 1l exhibit the application to tail planes. The horizontal tail is I9 iof which parts are the aps 20 and elevator 2l. 'I'he tail is hollow and is supplied from the fuselage 22 with air or other gases, as shown 4particularly in Figure 6. The air flows out the slots 23 and 24 to some extent at all times. s.

l When control is to befexperienrcedthe elevator v2I is rotated bymeans of vthe 'control'rod 25, Figure 9. The flap 2G is also rotated and together with the elevator provides a smooth curved contour on lone side of the tail plane. Also, the relation of the flap to the elevator changes so as to The jet issuing controls the boundary layer so that a large control force is provided on the tail Iplane.

The flap 20 is hinged to the main part of the wing at 26 and connected to the elevator at its trailing edge by the lug y2I formed -at 4one 'end into a `cylinder '2I`a which 'slides in a T=slot '28 Aformed in 'the wall'of 'theelevatorl'L The "lsl'ot has a varyingdepth so 'a'sto'vaiiythe'slots`23and v24 between the two parts. Thus in "theiposition shown `in Figure 8 vthens'l'ots'are S'm'a-ll while lin the position of Figure 9 the fslotfis large.

The iin and rudder'mayb'e constructed fin sim'- -ilar'rnannen For claim purposes Ilrefer to flaps lsuchfas 20, which are Vbathed -on'oiie s'ideon1y by the fm'a'in relative wind stream, 'as surface `flaps.

While I 'have illustrated certain i specific forms of the invention it -isto `be understood `that If`do not limit myself to these exactly but intend 'to claim my invention ybroadly as Vindicated by the claims.

I claim:

1. In Icombination in an aircraft, a wving on each-side of "the aircraftvhaving'a flap and Eslot, ailerons at the Aoutere'nds"of'the wings, each said slot leading into the wing interior land being located 'in 'the rear half of `the wing, and fa blower within the aircraft in communication with 'the wing 'interior to discharge outward power iets through said slots, said Ldischarge-slot being the rearmost slot in said wing iand being formedrto direct the 'slot `flow rearward substantially*along the Wing surface, control means operable coincidentally -to vary Athe slo'tows differetiallynd to rotate the flaps differentially both with respect to opposite wings, said control means being adapted to provide the strongest 'discharges'lot jet on-the wingwith vthe'down aileronjs'aidpower jets serving to produce .a rolling moment accompanied by 'afavorable `y'awing moment "2. In combinationinanaircraftfa, lollowwin'g having an induction slot and afdischarge sloti'n the same side surface Y'ofthe `wing f in' communication with the Awing interior 'and amova'ble trailing edge flap, Vafpowendriven blower Iwithin the aircraft -in'c'ommun'ication with said interiorit) induce 'an inflow through the Iinduction slot faid an'outflow jet through 'the discharge slotjsai'd discharge slot being formed to direct the slot rearward flow 'more Ealong than "normal to the wing surface, steering vmeans 'to /move the `opposite flaps differentially yand 'to con-trol 'the discharge slot flows in opposite wings differentially with thevforce 'of the yjet/on Ithe A4downflap wing being increased relative 'to that en lthe ltrafen wing, said dischargefslo'ts'l being aftv of :the induction slots in'each'wing'andben'gthe reari'nost Slots n the Wings, thejetfrointlediscliargeslot on'thedown 'ap wing'serving itolprovide -a'tlirs't to counteract thedrag from theilap whenl down.

3. In combination inan aircraft, a hollow wing main body and' a flap supported means-for' 'supporting said main' body and-nap in variable relation to form a lwing "on opposite sides of the aircraft, each said wing having adischarge slot in its upper surface in communication withlthe wing interior, said fiaps being rotatablev about spanwise axes, a blower withintheaircraft in communicationwith lthe wing interior to dischargea power jet through said slots, andsteering means to differentially control the ilaps and the slot flows :both with respectl to opposite wings with the force of the jet on the down-flap wing being increased relative to that on the up-llap wing to produce a rolling moment accompanied by a favorable yawing moment, said discharge slot being the rearmost slot in said wing and being substantially adjacent the nap so that the jet can b-e deflected effectively by the flap.

4. In combination in an aircraft, wing main bodies and rear flaps supported in variable relation to forma hollow wing on each side of the plane of symmetry having a discharge slot in its upper surface in communication with the wing interior, said rear flaps being rotatable about spanwise axes, a blower within the aircraft in communication with the wing interiors to discharge outward jet flows through said slots, said discharge slots being the rearmost 'slots in the wing and being formed to direct the jets rearward substantially along the wing surface, and means coincidentally to move the flaps and control the slot flows both differentially with respect to wings on opposite sides of said plane whereby to create a rolling moment and a favorable yawing moment, each said flap when in neutral having an upper external chordwise contour whose average radius of curvature is substantially less than the average radius of curvature ofthe upper aft portion of the chordwise contour of the said main body immediately ahead of its rear end but greater than the thickness of said aft portion forming an upwardly arched external airfoil surface.

5. In combination in an aircraft, a hollow wing on each side of the plane of symmetry having a discharge slot in its upper surface in communication with the wing interior and a flap movable about a spanwise axis, a blower within the aircraft in'communication with the wing interior to discharge jet flows through theslots, said discharge slots being formed to direct the slot ow rearward more along than normal to the surface, and means to create a rolling moment and a favorable yawing moment comprising means to control said slot flows differentially with respect to opposite wings with the force of the jet on the down-nap wing being increased relative to that on the up-ap wing, and means operable coincidentally with said control means to move the flaps differentially with respect to pposite wings, said discharge slots being the rearmost slots in the wing and being in the rear one-half of the wings so that the slot jets can be effectively deflected by the flaps. i

6. In combination in an aircraft, a hollow wing on each side of the plane of symmetry having a rearward directed discharge slot in the upper rear half of its surface in communication with the wing interior and a flap movable about a spanwise axis, said slot extending spanwise in the direction of the flap axis, and a blower within the aircraft in communication with the wing 'interior to discharge outward jet flows through .6 said slots, said discharge 4slots l being the lrearmostslots in the wing, and means to create a rolling moment and' aV favorable yawing moment by coincidentally moving the flaps'diiferentially and "controlling the slotV widths differentially so that the slot ofthe wing with the lower flap has the greater flow and the greater resulting forward reaction, each said discharge slot being succeeded at a vertical spanwise section by a curved surface of Athe wing whose minimum radius of curvature ssubstantially greater than the thickness of theflap at this same section.'

'7. In an aircraft a stabilizing wing composed of a wing main body and a plurality of movable surface elements, means for adjustably securing said elements in tandem at the trailing edge of said wing, and means to move one of said elements to alter the camber of the wing section and provide a chordwise convex surface, one side of the wing having a radius of curvature at the juncture of two said elements substantially greater than the thickness of the wing at the said juncture, said wing having a slot in its surface on the convex side formed to discharge over said convex surface of the rearmost of said elements toward the trailing edge, a blower within the aircraft in communication with said slot to discharge an outward jet flow therethrough, to develop a forward thrust, said discharge slot being the rearmost slot in said wing, said jet and surface of large radius of curvature serving to facilitate the production of greatlift for a minimum of power expenditure by the blower.

8. In combination, a wing main body and a trailing edge flap body, means for supporting said bodies in variable relation to form a wing, leaving a discharge slot communicating with the wing interior and discharging a jet of air above and below said Itrailing edge flap body, a surface ilap hingedly` 'supportedabout a spanwise axis on said main body and slideably supported on said trailing edgeV flap body to form part of the said wing and to complete the airfoil contour thereof, means to depressv said trailing edge ap body, one said trailing edge flap having a chordwise slot therein to accommodate a sliding lug, and the surface flap having a lug adapted to slide chordwise in said yslot to govern the rotation of the surface ap about its said hinge axis in response to the change in position of said trailing edge ap, and blower means to discharge a jet through said discharge slots.

9. In combination, a wing main body and a trailing edge flap body, means for supporting said Y bodies in variable relation to form a wing, a sur- Iface flap hingedly supported about a spanwise axis on one of said bodies and slideably supported on the other to form part of the said wing and to complete the airfoil contour thereof, means to depress said trailing edge flap body, one of said bodies having a chordwi'seV slot therein to accommodate a sliding lug, and the surface flap having a lug adapted to slide chordwise in said slot to govern the rotation of the surface flap about its said hinge axis, said chordwise slot having a variable depth below the surface of said body to. provide a variable gap between the said body and surface flap for different positions of said iiap body, and blower means to discharge a flow of air through said gap.

10. In combination inan aircraft, a wing main body and a trailing edge iiap body, means for supporting said bodies in variable relation to form a Wing on each side of the vertical plane of sym- 7 metry of the aircraft, with their upper surfaces overlapping, the upper chordwise contours of the main body and flap being convex and forming at their juncture a concavity having a substantial depth below a chordwise line .tangent to the upper contour of the wing on opposite sides of said concavity, said wing having a slot in its upper rear half of the surface in communicationvwith the wing interior, a blower Within the aircraft in communication with the Wing interior to discharge a ow through said slot, said discharge slot being the rearmost slot in the said upper surface, and Vmeans to rotate the opposite flaps dif'- ferentially, in the neutral position'of the fiap the upper chordwise contour of said flap having a smaller average radius of curvature over the central half of its chord length than the average radius of curvature of said main body upper contour along its rear one-half of its chord length, said ap in the neutral position having its upper contour above a line through the trailing edge of the wing and tangent to the rear upper edge of said main body. l Y

EDWARD A. STALKER. 

